ZingChart is a JavaScript charting library that supports stock and volume charts. To get started, I recommend reading our Stock Charts Tutorial, just to get an overview of what you can do with the chart type. Here's a basic stock and volume chart created with blended scales. The "stock" and "volume" portions share the same x-axis time-series scale.

http://demos.zingchart.com/view/PVTPGND4
There are many ways to customize this chart type. Here is another example that incorporates a zooming scrollbar and dynamic labels/crosshairs. Click the links to interact with the chart.

http://demos.zingchart.com/view/ULASOO3O
I'm on the ZingChart team. Let me know if you have more questions. Thanks!